Waveguides and Remote Transducers for Acoustic Thermometry
Acoustic thermometers normally embed small acoustic transducers in the wall bounding a gas-fiUed cavity resonator. At high temperature, insulators of transducers loss electrical insulation and degrade the signal-to-noise ratio.One essential solution to this technical trouble is to couple sound by acoustic waveguides between resonator and transducers. Resonance frequency perturbations arising from waveguide ducts have to be quantified and corrected in order to maintain the required accuracy,. In this paper, perturbations to longitudinal modes caused by circular ducts were investigated by applying the transmission line theory. The resonance frequency shifts and the half-widths increases were obtained as functions of the ducts radius, length, and locations of the transducers along the duct length. For one case of the waveguides of 1.4 mm in diameter and 2 m in lenght, the resonance frequency shift △f/f and half-width increase△g/f were estimated to be -0.23×10-6 and 40×I0-6 for the third longitudinal mode at 273.16 K and 0.1 MPa, respectively.
Metrology Acoustic thermometry Waveguide
LIN Hong Keith A.Gillis Michael R.Moldover ZHANG Jin-tao
Heat Division, National Institute of Metrology, Beijing 100013, China Process Measurements Division, National Institute of Standards and Technology, Maryland 20899, USA
国际会议
2008年国际温度与热物性测量会议(TEMP BEIJING 2008)
北京
英文
42-45
2008-10-20（万方平台首次上网日期，不代表论文的发表时间）